The invention relates to drying fans, including for water damage restoration and other applications.
In the water damage restoration industry, fans are used for drying a water damaged structure, including carpeting, furniture, framework, etc. If water can be evaporated quickly, damage can be minimized. The fans move air over the water damaged surfaces at high velocity. The two types of fans typically used are axial propeller type fans and centrifugal squirrel cage type fans. The present invention is directed to improvements in axial fans because of their lower electrical current requirements.
The corner between a wall and a floor is the most difficult area to dry and takes the longest time to dry. The present invention addresses and solves this problem with an axial flow fan. The invention has particularly desirable application to water damage restoration, though may be used in other applications therebeyond.
The present invention focuses the drying air toward the problem area of the room. In the preferred embodiment, this is accomplished by a desirably shaped exhaust duct downstream of the axial fan blades, which exhaust duct both: a) provides expansion of the airflow where desired; and b) directs the airflow where desired. In one particularly desirable embodiment, the exhaust duct geometry directs expansion of air into a problem area such as a corner by allowing the air to expand predominantly only in one direction chosen to be the direction of the most difficult to dry location in the room.
In one aspect, a downwardly sloping ramp is provided in the exhaust duct. The ramp is located at a downstream location spaced from the axial fan blades as far as possible, and the ramp pitch is minimized, due to the inability of the axial fan blades to produce static pressure. Without static pressure, if one attempts to expand the air too quickly, the result is a dramatic loss of velocity. The length of the duct downstream of the blades must be optimized. Too long of a length is a waste of material, whereas too short of a length will not provide desirably directed airflow.
In the preferred embodiment, the length of the duct upstream of the axial fan blades is minimized, to allow the blades to be supplied or “fed” with as much air as they can possibly move, and to avoid starving the blades for supply air. An intake cowling is provided and enhances this supply air.
In further embodiments, the axial fan blades are moved as close as possible to the wall and/or floor. This is desirable so that intake air does not have to change direction and accelerate before becoming exhaust air, or only has to undergo minimal directional change. The air moving through the fan stays close to the wall and/or floor in order to dry the wall and/or floor, particularly at the corner. Keeping the blades close to the wall and to the floor also eliminates the need for large radiused round cowling sections at the wall and/or the floor because the wall and floor upstream of the intake acts as a section of intake “duct”. This “duct” helps the air to establish an axial direction of flow, and hence aids in supplying the blades with intake air. This intake air also aids in structure drying. In further embodiments, the remaining cowling sides opposite the wall and the floor may have maximized radii in order to aid air supply, with the limiting factor being exterior housing dimensions. In preferred embodiments, all exterior housing surfaces are shaped for portability and storable stackability.
Further desirable aspects include stator vanes removing downstream rotation from the air and transferring same into useful axial air velocity. In another aspect, stand mounting pads are provided with threaded inserts, allowing the operator to mount the fan quickly on a stand and pointed in a desired direction. In another aspect, motor mounting pads are provided, allowing for rigid assembly of the motor to the fan housing. In another aspect, desirable electrical component location is provided, allowing the operator to quickly and easily access and use the controls without bending over, and to quickly and easily access and use the controls in each of a first fan orientation providing a counterclockwise drying flow pattern around a room, and a second fan orientation providing a clockwise drying flow pattern around a room. In another aspect, a handle is offset to one side so that the operator does not have to carry the fan farther away from his/her body. The handle is also parallel to a flat side of the fan such that the operator does not have to twist his/her arm when carrying it nor have obstruction to the natural motion of his/her legs when walking. The handle is located close to the center of gravity, and when held, the fan hangs close to vertical and does not interfere with walking. In a further aspect, interlocking nubs are provided, allowing multiple fans to be stacked on one another. In another aspect, a cord wrap is provided, storing the cord within the circumscribing cuboid, keeping the cord out of the way during storage and transfer. In another aspect, variable height legs are provided, establishing a selectable pointed airflow angle, and allowing for air circulation below the fan.